net: ip: make ip_mc_validate_source() return drop reason

Make ip_mc_validate_source() return drop reason, and adjust the call of
it in ip_route_input_mc().

Another caller of it is ip_rcv_finish_core->udp_v4_early_demux, and the
errno is not checked in detail, so we don't do more adjustment for it.

The drop reason "SKB_DROP_REASON_IP_LOCALNET" is added in this commit.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index 62a60be1db840646b5ecd3d1da3fd40624432804..a2a1fb90e0e58961182b4cbaa1ad344eb1447677 100644 (file)
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -78,6 +78,7 @@
        FN(IP_INNOROUTES)               \
        FN(IP_LOCAL_SOURCE)             \
        FN(IP_INVALID_SOURCE)           \
+       FN(IP_LOCALNET)                 \
        FN(PKT_TOO_BIG)                 \
        FN(DUP_FRAG)                    \
        FN(FRAG_REASM_TIMEOUT)          \
@@ -383,6 +384,8 @@ enum skb_drop_reason {
         * 2) source ip is zero and not IGMP
         */
        SKB_DROP_REASON_IP_INVALID_SOURCE,
+       /** @SKB_DROP_REASON_IP_LOCALNET: source or dest ip is local net */
+       SKB_DROP_REASON_IP_LOCALNET,
        /**
         * @SKB_DROP_REASON_PKT_TOO_BIG: packet size is too big (maybe exceed the
         * MTU)

diff --git a/include/net/route.h b/include/net/route.h
index 0a690adfdff527262ab1f385bf76a16e1f63be07..e2e1922c58fb01d462bbe3081af3665531d6833e 100644 (file)
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -199,9 +199,10 @@ static inline struct rtable *ip_route_output_gre(struct net *net, struct flowi4
        return ip_route_output_key(net, fl4);
 }
 
-int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-                         dscp_t dscp, struct net_device *dev,
-                         struct in_device *in_dev, u32 *itag);
+enum skb_drop_reason
+ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
+                     dscp_t dscp, struct net_device *dev,
+                     struct in_device *in_dev, u32 *itag);
 int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                         dscp_t dscp, struct net_device *dev);
 int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b20316789baa71e27966a6b6ed7af607a00c92bf..ef0b5ffda8435e5982dda150665b248948af3b28 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1678,34 +1678,37 @@ struct rtable *rt_dst_clone(struct net_device *dev, struct rtable *rt)
 EXPORT_SYMBOL(rt_dst_clone);
 
 /* called in rcu_read_lock() section */
-int ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
-                         dscp_t dscp, struct net_device *dev,
-                         struct in_device *in_dev, u32 *itag)
+enum skb_drop_reason
+ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,
+                     dscp_t dscp, struct net_device *dev,
+                     struct in_device *in_dev, u32 *itag)
 {
        enum skb_drop_reason reason;
 
        /* Primary sanity checks. */
        if (!in_dev)
-               return -EINVAL;
+               return SKB_DROP_REASON_NOT_SPECIFIED;
 
-       if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr) ||
-           skb->protocol != htons(ETH_P_IP))
-               return -EINVAL;
+       if (ipv4_is_multicast(saddr) || ipv4_is_lbcast(saddr))
+               return SKB_DROP_REASON_IP_INVALID_SOURCE;
+
+       if (skb->protocol != htons(ETH_P_IP))
+               return SKB_DROP_REASON_INVALID_PROTO;
 
        if (ipv4_is_loopback(saddr) && !IN_DEV_ROUTE_LOCALNET(in_dev))
-               return -EINVAL;
+               return SKB_DROP_REASON_IP_LOCALNET;
 
        if (ipv4_is_zeronet(saddr)) {
                if (!ipv4_is_local_multicast(daddr) &&
                    ip_hdr(skb)->protocol != IPPROTO_IGMP)
-                       return -EINVAL;
+                       return SKB_DROP_REASON_IP_INVALID_SOURCE;
        } else {
                reason = fib_validate_source_reason(skb, saddr, 0, dscp, 0,
                                                    dev, in_dev, itag);
                if (reason)
-                       return -EINVAL;
+                       return reason;
        }
-       return 0;
+       return SKB_NOT_DROPPED_YET;
 }
 
 /* called in rcu_read_lock() section */
@@ -1715,14 +1718,14 @@ ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 {
        struct in_device *in_dev = __in_dev_get_rcu(dev);
        unsigned int flags = RTCF_MULTICAST;
+       enum skb_drop_reason reason;
        struct rtable *rth;
        u32 itag = 0;
-       int err;
 
-       err = ip_mc_validate_source(skb, daddr, saddr, dscp, dev, in_dev,
-                                   &itag);
-       if (err)
-               return SKB_DROP_REASON_NOT_SPECIFIED;
+       reason = ip_mc_validate_source(skb, daddr, saddr, dscp, dev, in_dev,
+                                      &itag);
+       if (reason)
+               return reason;
 
        if (our)
                flags |= RTCF_LOCAL;